March 6, 2013

Imagine All The People: fMRI Shows Who You’re Thinking About

An international team of researchers led by Cornell University reveals that it is possible to tell who a person is thinking about by analyzing images of his or her brain.

Nathan Spreng, assistant professor of human development in Cornell's College of Human Ecology, and his colleagues demonstrate that our mental models of people produce unique patterns of brain activation, which can be detected using advanced imaging techniques.

"When we looked at our data, we were shocked that we could successfully decode who our participants were thinking about based on their brain activity," said Spreng.

The team, which includes members from University College London, Harvard University and York University, say that understanding and predicting the behavior of others is a key to successfully navigating the social world, yet little is known about how the brain actually models the enduring personality traits that may drive others' behavior. This allows people to anticipate how someone else will act in a situation that may not have happened before.

The research team asked study participants to learn about the personalities of four people who differed on key personality traits. The 19 young adults were then given different scenarios, such as an elderly person getting on a bus when there were no available seats. They were asked to imagine how a specified person would respond to this scenario. The participants' brains were scanned using functional magnetic resonance imaging (fMRI), which measures brain activity by detecting changes in blood flow, while they were engaged in the task.

The scientists found that each of the four personalities were associated with different patterns of brain activity in the medial prefrontal cortex (mPFC). This allowed the team to accurately identify which person was being imagined based solely on the brain activation pattern.

Based on these results, the team suggests that the brain codes the personality traits of others in distinct brain regions. The information is then integrated in the mPFC to produce an overall personality model used to plan social interactions.

"Prior research has implicated the anterior mPFC in social cognition disorders such as autism and our results suggest people with such disorders may have an inability to build accurate personality models," said Spreng. "If further research bears this out, we may ultimately be able to identify specific brain activation biomarkers not only for diagnosing such diseases, but for monitoring the effects of interventions."